We will investigate the mechanism by which the product of phage lambda gene Q (and the corresponding protein of phage phi82) promotes late gene expression during phage growth. We will continue to develop methods to purify this protein, and will determine how the purified protein interacts with components of transcription or translation to promote gene expression. In particular, we will investigate the possibility that this regulation occurs through antitermination of a leader transcript. In addition, we are continuing to characterize the activity of the E. coli recA gene product, a central element in the expression of SOS functions such as mutagenic DNA repair. We have shown that the recA protein promotes cleavage of bacteriophage repressors, a reaction that leads to the induction of prophage in the bacterial cell. We will investigate the relation of this activity to other functions of recA protein, and we will attempt to determine how the activity of recA protein is regulated.